Surgical endoscopy is a surgical technique of using small diameter tools such as graspers, forceps, retractors, dissectors and clamps specially designed to be inserted through small openings in the body to perform operations within the body. The surgeon performing the surgery often cannot see the operation directly, and must watch the procedure on a video monitor fed by an endoscopic camera or through an endoscope. Endoscopic surgery may be preferable to open surgery because open surgery requires large incisions, essentially opening the body cavity completely in order to perform surgery deep within the body. The terms "laparoscopic surgery," and "arthroscopic surgery," are often considered to be types of endoscopic surgery, but are commonly used synonymously to refer to endoscopic surgery and minimally invasive surgery.
The surgeon performing such a surgery makes one, or a few, small incisions and inserts specially designed tools having small profiles through the incision and advances the tools to the desired location in the body. Long tools may be used to access over substantial distances from the incision deep into the body. Viewing the tools and the anatomy through an endoscope or on a video display from the endoscope, the surgeon can perform a wide variety of activities, including dissecting, retracting, cutting and suturing, necessary for a wide variety of surgical procedures.
In certain types of surgery dealing with elongate structures, for example blood vessels and long bones, it is desirable to dissect and/or retract tissue away from the elongate structure along at least a portion of their length. This may be accomplished in order to facilitate introduction of a tool or implant (temporary or permanent) alongside the structure, or to harvest at least a portion of the structure, such as a length of a vessel. In some instances, it may also be desirable to provide retraction of the tissue away from the elongate structure in the dissected region to create a working and/or a visualization space. In addition it is advantageous that the retraction be accomplished in a manner which minimizes blockage of surgical access to the dissected region thereby providing ample working and/or visualization space.
Many endoscopic surgical procedures may usefully employ such methods of dissecting and/or retracting tissue away from elongate structures. For example, in a blood vessel harvest, tissue is dissected away from the vessel and is then retracted to provide working and visualization space for ligating side branches and for completely separating the vessel from the surrounding tissue. Further, in the emergency treatment of long bone trauma, such as a fracture, it is often necessary to dissect along the bone to create space for plating. In both of these instances it is desirable to minimize the incision length, thereby accelerating the recovery process and its associated pain and reducing risk of infection. There are many inherent difficulties encountered in treating elongate structures using endoscopic techniques. For example, typically these procedures are performed through a single incision overlying one end of the region of the body to be treated. Hence, long tools must be used to reach from the incision site to the far end of the elongate structure being treated. In many situations, these long tools must navigate tortuous paths to reach the desired location in the body. These situations present several drawbacks in current methods. Firstly, it is difficult to advance long tools and to precisely position the distal end of the tools due to the extensive length of the tools and inherent visual uncertainty. Moreover, even after they are positioned, long tools are generally harder to maneuver and to operate than similar instruments having shorter lengths. Also, the long, narrow path to the desired location severely limits the maneuverability of the distal end of the instrument. This creates even greater difficulties and is especially undesirable where the orientation of the instrument is critical.
Many types of expanding devices which can be used to dissect and/or retract tissue for use in endoscopic procedures have been disclosed. A feature common to each of these devices is a small initial (or contracted or unexpanded) profile such that it can be inserted through a small incision. Once inserted, the device can be expanded to exert force on surrounding tissue to perform dissection and/or retraction. Further, the device must be capable of being contracted after use so that it can be removed through the same small incision. The designs of known devices varies greatly. For instance, devices have been disclosed which utilize mechanical means such as expanding arms, or inflatable apparatus which expands by pressurizing with fluid, or a combination of mechanical and inflatable mechanisms. For example, in commonly assigned U.S. Pat. Nos. 5,667,520 and 5,772,680 and U.S. application Ser. No. 08/927,371, the disclosures of which are hereby incorporated by reference in their entirety, various apparatus comprising mechanical, inflatable and combination mechanical/inflatable devices are disclosed which can be utilized to dissect and/or retract tissue. Depending on the nature of the application and surgical exposure desired, the apparatus are disclosed as having one or more expanding portions typically disposed on an insertion tool such as a blunt dissector or tunneling assembly, scope, rod, tube or other suitable structure. In many instances, an inflatable device provides superior performance because: (1) it can be contracted into a very small profile; (2) it is easily and variably expandable; (3) it can be readily formed into many different shapes specially designed for the particular procedure; (4) it can be made of transparent material to allow visualization through it; (5) the expansion force can be specifically and accurately directed to the desired tissue; and (6) the amount of force applied to the tissues can be precisely controlled.
In endoscopic procedures, an alternative to accessing the remote portions of a desired region of the body from the initial incision is to access the site from directly above the location. First, the region of interest in the body is dissected and/or retracted through an initial incision using the endoscopic techniques described above. Then, the surgeon locates the surface of the body directly above the site from the exterior of the body, such as by using the endoscope light which is often visible through the surrounding tissue. Finally, a small incision or puncture is made from directly above the site to the required depth. This method has the advantages that the surgeon is closer to the region of the body to be treated and relatively shorter instruments can be used. Furthermore, the shorter distance to the site of the procedure improves maneuverability and eases the use of the instruments. This method provides significant advantages with only a small increase in the total length of incisions.
The method of using additional incisions directly above the previously retracted region of an endoscopic surgery, however, requires that the retractors used provide direct access to the desired site from above. Although some of the inflatable retractors/dissectors described above are suitable for retracting elongate regions and can be inserted through small incisions and provide excellent dissection and retraction, they do not provide access through the overlying tissue and around or through the retractor. Instead, these prior elongate inflatable retractors/dissectors are configured to facilitate access along the path from the initial incision and therefore have solid surfaces which block direct access to the region from positions opposite the device. Although some of the previously disclosed inflatable devices described above are suitable for retracting elongate regions, none of the devices leaves adequate surgical access to the anatomy through and around the device.
Accordingly, there exists a need for an apparatus and corresponding method of using the apparatus which is suitable for dissecting and/or retracting elongate regions while also providing sufficient access to the region through overlying tissue and around or through the apparatus. Further, the apparatus should preferably be inflatable and adapted for use in endoscopic surgery.